


The Blind White Sea-Snake

by TheWaffleBat



Series: Home From All The Ports [15]
Category: Assassin's Creed - All Media Types
Genre: Blood, Brother-Sister Relationships, Canon-Typical Violence, Dad!Herodotus, Father-Daughter Relationship, Gen, Isu, Mythology - Freeform, Sea Monsters
Language: English
Status: Completed
Published: 2019-04-23
Updated: 2019-04-30
Packaged: 2020-01-16 16:29:21
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 3
Words: 3,386
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/18525298
Author URL: https://archiveofourown.org/users/TheWaffleBat/pseuds/TheWaffleBat
Summary: Herodotus’ head snapped to her, a grin bright on his face. “Kassandra!” He said, darted forward when she drew close and dragged her into leaning over the rail with him; swept his hand out towards the sea cave huge on the cliff-face, yawning deep into the heart of the island. “Look!” He said. “Kassandra look! A ruin! An Isu ruin!”Herodotus notices an Isu ruin, and because Kassandra loves him she takes him inside. There is more than just sand at its heart.





	1. Chapter 1

**Notes for the Chapter:**

> Title taken from Rudyard Kipling's _In The Matter Of One Compass._

Poseidon was calm as the Adrestia sailed close to a cluster of islands, blue and endless beneath the midday sun. They were a little way out from normal sailing waters, but not so far that they weren’t half a day’s hard travel from the Pirate’s Isles so Kassandra wasn’t too worried as Barnabas guided them through. She looked to the notice she’d found, and scowled at the narrow strait between the largest and smallest islands they were using as a shortcut; the islands were long, and it would be a long delay having to go around. “Careful!” She called. “Or we’ll all be swimming back to Greece!”

“Aye Captain!” Said Barnabas, and shouted the rowers into slowing the ship until the Adrestia was crawling along.

Mercifully, the strait was not so narrow that the Adrestia couldn’t pass through. The rocks scraped uncomfortably against its flanks, making it shudder and heave in agitation until the rowers put oars to the islands’ tiny cliffs and pushed the Adrestia squarely in the middle, but otherwise they passed through unharmed. The crew cheered as the ship hit deeper, safer waters, cheered louder when Kassandra called for an hour’s break because the rowers deserved it.

Ah, she thought - there was nothing she loved more than the sea. She’d never quite understood Poseidon’s call while she’d been on Kephallonia, young and small and hiding beneath Markos’ wing as she watched sailors at the docks, who were anxious to be back out on the water. She remembered too keenly being tossed and turned on the waves in her tiny boat, the long hours fighting against the wind to reach the distant shore because even an empty island was a port and a shelter; why did those old men with wind-burned faces turn sad eyes on the sea?

She smiled at Barnabas, because they both knew that a ship, a true ship like the Adrestia beautiful as it cleaved through the water, sails red as the sunset skies, was as great a joy to sail through Poseidon’s wildest furies as that tiny tub she’d been stranded in was a terror, and there was no real comparison between them. Looked to Deimos scowling at the lowered sail, caught his eyes and gave him a smile, too, because he loved the sea as she did, even if his excitement was more for the upcoming battle with the pirate than anything else.

But Kassandra turned from them both, looked with a frown to Herodotus leaning over the rails to stare at the largest island. “Herodotus?”

Herodotus’ head snapped to her, a grin bright on his face. “Kassandra!” He said, darted forward when she drew close and dragged her into leaning over the rail with him; swept his hand out towards the sea cave huge on the cliff-face, yawning deep into the heart of the island. “Look!” He said. “Kassandra look! A ruin! An Isu ruin!”

Kassandra squinted. “I don’t see anything.”

“There!” Said Herodotus, frustrated. “See it? The arch, the pillars, the doorway?” He jabbed his hand towards it urgently. “There! My daughter, we must go to see it! Who knows what could be inside? Perhaps more messages from Alatheia, or from other Isu, or perhaps something for Leonidas’ spear! There might be books! Or houses!” Giddy excitement made him shiver and he grinned at the cave. “We know nothing about the Isu’s day-to-day; did they have rooms in large complexes? Did they have families or were they advanced enough to never need bother with it? Or perhaps this is a _workshop_ ,” Herodotus breathed, going still. “Kassandra, _please_ \- what if they have diagrams in there? Or manuscripts; oh, _manuscripts_!”

Deimos, glancing at Kassandra, looked towards the mouth of the sea cave where an Isu-made pillar - barely a stump, really; most of it fallen into the blue water flowing inwards from the sea - marked the stone pathway leading deeper where stone gleamed, too high to be wet and too smooth to be the cave’s rough walls. He remained unimpressed. “It’s a cave. There are many like it, old man.”

Kassandra did have to agree - it was only a cave, and just because there was a doorway didn’t mean it led to anything important. She hadn’t found many Isu ruins, but the few she had found that wasn’t Atlantis or the forge making Leonidas’ spear better had been largely empty and useless. She had seen many caves like it, kept away from the sea by the wide, flat beach of sand and scattered seaweed and the occasional large, flat rocks. It wasn’t so remarkable.

“But the Isu were _here_ ,” Said Herodotus, gesturing around them. “Why? The entire reason the pirate on that notice of yours, Kassandra, is here is because this is the middle of nowhere. _Why here_ of all places? Is it older than all the others, and abandoned when they came to the mainland? Was it so important or so dangerous it had to be kept seperate?”

Deimos shrugged, looking both bewildered, bored, and irritated. “Oh, go take your old man on his walk,” He huffed, turning for the hatch that led below where Nikolaos was holding it open for him. “Barnabas will watch the ship for an hour.”

Kassandra looked to the cave again, and sighed to herself. There was the familiar itch in her hands, deep in the bones of her arm, that said to go inside and steal everything not nailed down; glanced at her sword and spear on her hip and grimaced because Isu weapons were _fantastic_ \- so difficult to dull she’d forgotten where she’d put her whetstone and their strange power humming in her blood letting them slice through the toughest armour or bone - but also usually meant she had to fight something dangerous and either mad with fury or just mad, and very often both.

But _weapons_ , and _gold_ , and the greater joy of making Herodotus happy, and maybe the even greater joy of pissing Deimos off. She grinned at Deimos, and he narrowed his eyes at her, pausing on the steps, because _oh yes_ \- she had forgotten that particular joy after the thing with Leda, discovered when Deimos came to trust that their teasing was only play and endless fun ever since, but it would never stop being entertaining no matter for how long it slipped her mind.

“Alright, Herodotus,” Kassandra said, letting her smile grow wider and delighting in Deimos’ eyes growing narrower. “We’ll go to the ruin - an hour or so looking through it can’t hurt. And perhaps Deimos would like to come with?”

“No.”

“After all,” Kassandra continued, turning to Herodotus’ joy-bright face. “We cannot, after all, know what’s in there. There might be a Cyclops-”

“Or bones.”

“- Or something else equally dangerous. You never know.”

Deimos hissed like a scorned cat. “No!” He said, while Kassandra and Herodotus turned beaming smiles on him. “No, I will not! Take Nikolaos with you, or Stentor. _No_ ,” He insisted, scowling. “I will _not_.”

**Notes for the Chapter:**

> I don't even know anymore. Just, have another multichapter.


	2. Chapter 2

“It would be very easy for my sword to slip in there, Kassandra; it might find itself accidentally embedding itself in your guts seven times. Especially if it’s dark.”

Kassandra only smiled at Deimos, and helped Herodotus up from the white, sandy beach and onto the high lip of the stone path bridging the lake of seawater flowing into the cave. She didn’t even make it smug just to aggravate him, because Deimos wouldn’t kill her and he _was_ trudging along several steps behind; kicking the sand and huffing annoyance, true, but _following_ when he could very easily go back to the Adrestia as he clearly wanted to.

And Herodotus was right, there _was_ a doorway blocking off the end of the sea cave, its strange metal and stone still smooth and beautiful; no pockmarks from the salt and sea and wearing of the waves on its wall, no tarnish on its decoration or supports or whatever they were. Not even a weed taking root on it below the water. But like the forge for Leonidas’ spear the doors opened at her touch, stone grinding against stone in little clouds of dust kicked up by the mechanism or magic that worked it.

She paused, listened a moment; there was only the  _plink_ of dripping water echoing from deep inside the ruin, and so she lit her torch and led the way inside.

Herodotus ducked below the arch of the doorway and crowded close at Kassandra’s back, closer still when the yawning darkness all around pressed in on the little circle of firelight, and followed as Kassandra started down the stairs leading deep below the earth. Deimos, behind Herodotus, shivered at the cold hung in the too-still air, and Kassandra spared him a glance as she helped Herodotus down the narrow steps, grimacing at him with real sympathy because she hated it too; Atlantis’ clammy air had been just as dead against her skin as the dry heat billowing up from far below.

It took a long while to reach the bottom, carefully feeling out each step and helping Herodotus down them, straining for sight and sound of anything dangerous. But nothing had jumped out at them when they eventually reached the bottom. Well, there had been a spider, but it wasn't anything Kassandra or Deimos could use as an excuse to go back outside. There was only another door that Kassandra opened, and when they stepped through there was almost _less_ than nothing; the room they entered a huge, circular cavern whose floor was one half filled with sand and only sand and the other half filled by what looked like a sea made miniature - all lit up by lights embedded on the ceiling, a deep, too-warm red.

“Incredible,“ Breathed Herodotus, stepping into the cavern and gazing at everything all around, so Kassandra supposed that as long as he was happy it wasn’t an entirely wasted trip. Herodotus pointed up at the walls arching smooth and high overhead. “See there? And there? This is an arena, it seems; those look to be spectator’s seats, or perhaps simply some form of observatory. I wonder what they used this for,” He murmured to himself.

Kassandra shrugged, even though Herodotus wasn’t paying attention - what did she know? The Isu just confused her, so she didn’t really pay them that much mind - and turned, instead to looking at the arena all around, wandering across its huge expanse of sand. Deimos hovered by the door, arms crossed across his chest and hunched inwards against the press of stone all around.

“Can we go?”

“Soon,” Promised Herodotus, stooping down to look at some designs cut into the wall. “Hmm. Kassandra, you’re good at reading these sorts of things; what do you make these cracks? Natural wear and tear, do you think? Though it might be battle damage, I suppose.”

Kassandra bent down to look at them with him, the cracks fanning out from low to the ground where something had hit it, huge and heavy; they spanned out to well above even _her_ head. It was made by something blunt, but long, too. She frowned at it. “Battle damage,” She told Herodotus. “Normal wear would show delicate cracks, or crumbling, or peeling layers - it depends on the stone. _These_ cracks are too wide and concentrated.” She stepped back, turned her frown on all the walls. “They kept something big in here,” She said, “And strong; see how many cracks there are?”

“Bloodstains, too,” Said Deimos, pointing to strange-coloured splatters on the walls. “And bones.”

There were many, many bones, scattered across the sand. She crouched down at one close to the center, a heap that looked mostly intact. When Kassandra looked at them the bones were human; all of them flung across the arena, as far as she could tell. Some were crushed, ribcages caved in, others were shattered, the backs of skulls cracked open. Flung against the walls, maybe? It would explain the stains. There were some swords scattered in the sand, too; bronze xiphos, some shattered and most blunted and edges curling around where they’d struck something too tough for it to cut.

A monster, at least as tall as the cyclops she’d faced and almost certainly longer; Kassandra looked to the sand, the curved ridges like dunes making familiar twisted tracks. A snake of some kind, molded by the Isu and made to fight. She glanced over the bones again - not all of them were ancient.

Oh, this wasn’t good. “We need to leave,” She said, looked to Deimos who nodded and pulled Herodotus back to the doors far across the sandy arena, no longer stood sullen under the fear hardening her voice. “Right now. I think there’s something asleep in here and I don’t want to be around when it wakes up.”

Deimos nodded again, hissed something to Herodotus while Kassandra carefully picked her way through the snake tracks curving huge and tall all around her. The sand was packed tight beneath her feet, dry but solid and it didn't move beneath her weight - not much, anyway - and she froze when near the water it shifted because _it shouldn't move_ , hissing as it slid off a huge, white-scaled coil rising up from the ground, thicker than Kassandra was tall. A hiss rumbled through the ground, loud as a roar as a single, dead eye opened; the horned head of the fish-scaled snake rising up, jaws filled with blade-sharp teeth opening wide, when it noticed her.

**Notes for the Chapter:**

> Fun fact this chapter was twice as long before my computer decided to crash, losing everything I added to it, so I'm sorry if it's a bit short.


	3. Chapter 3

Kassandra froze under the snake’s dead-eyed gaze, its rumbling hiss droning, grating against her ears. Its crown of horns flared out around its head as it tasted the air, grey-banded coils sliding through the sand as easily as water. It hissed again, jaws opening wider, horns flaring out even more as the hiss rose to the closest it could come to a scream.

She took a step back while it searched for her, head ducking and weaving through the air as it tasted. Another, and another, and another; edging back to Herodotus and Deimos waiting by the doors. Kassandra stepped carefully around the piles of bones, the shattered halves of swords whose _clink_ ing together might give her away. Another step back, closing her eyes against the rush of blood rising like the snake’s furious roar in her ears as it tasted where she’d stood in its shadow; breathed deep against the ache twisting high in her chest, tight around her heart because _fucking hel_ , she could kill most anything but she really, _really_ didn’t want to try her luck with Cerastes.

Cerastes uncoiled, sweeping through the sand, _below it_ , gods! Fuck, there was nothing for it, not with it’s coils coming dangerously close to Deimos, his sword unsheathed as he herded Herodotus against the walls, harder and harder as each pass of the coils came closer and closer.

Kassandra dashed across the sand, right in front of its snout. “Here!” She called, ripped her sword from its sheath and banged it against her spear, the ring of it as loud and shrill as her shout made loud by the fear strangling her guts. “Over here!” She shouted again, Cerastes’ head snapping to her, following as she ran back to the other side of the arena.

“ _Are you completely mad!_ ” Deimos demanded.

Cerastes paused. “This way!” Said Kassandra. Cerastes continued to follow, horns folding back as it dove beneath the sand. “Deimos, try and open the doors!”

“And leave you to die? Brilliant plan, Kassandra!” Deimos said, throwing his hands to the air while Cerastes shifted below the sand, though Kassandra had no idea what it was doing. “Absolutely wonderful! Oh yes, Barnabas will be _thrilled_ when I tell him his daughter is a madwoman who _let herself be eaten by a giant fucking snake!_ ”

“Have you got a better idea?”

“Oh just kill it Kassandra!” Said Herodotus. “We both know you will!”

Kassandra bared her teeth at him, resenting that it was true and resenting even more the little curl of disappointment beneath the fear in his voice because it wasn’t like she _meant_ to kill the Isu’s monsters, it was just that she cared more about her life than theirs and becoming a wet smear against a wall wasn’t how she wanted to go. When she died she wanted her bones thrown to the sea, not abandoned in some Isu lair or in Cerastes’ white-bellied gut.

But she said nothing, held her sword tight as she pressed her back against the arena wall. Below the sand Cerastes continued to shift and settle, the sliding sand betraying where it where it waited.

Kassandra licked her lips, adjusted her grip on her sword and spear. What was it doing? Was Cerastes waiting for her to move? Trying to work out where she was? It couldn’t see her, clearly. She slid her foot through the sand, not far enough that she was unbalanced from the fighter’s stance but enough that Cerastes could work out she was right in front of it. The sand hissed across Cerastes’ scales, the lump of it moving just a little; just enough that Kassandra froze again, drawing back against the wall.

She glanced at Deimos, who shrugged at her, frowning at Cerastes lying in wait just beneath their feet.

Fuck it; she ran. Across the sand, close to the wall and Cerastes exploded from the ground, a roar hissing high in its fish-scaled throat as it lunged. Kassandra rolled under it, squeezed her eyes shut against the stinging sand and _thud_ ; it’d hit the wall. Kassandra leapt to her feet and slashed blindly over her head, Cerastes’ scream telling her she’d hit the mark and she stabbed her blade deep, deeper -  _dragged_ the blade through muscle and scale, blood running hot down her arm.

Cerastes reared back, lunged again but made slow by pain, screeching as its wounded belly scraped across the ground; Kassandra dodged, barely kept her balance when Cerastes’ head thudded into the ground and she shoved her sword into its eye.

 _Shit_! Bad idea, terrible idea - Cerastes whipped its head back, shouts mangled by the screeching wind as some damnable instinct told Kassandra to hold onto the hilt, grabbing for its horns and desperately holding on as Cerastes whipped its head like an unbroken horse. Its scream rose high and thin and Kassandra kicked the blade deeper, deeper, _damn it_ deeper again when it continued to thrash.

Kassandra grit her teeth, kicked the blade again and Cerastes shuddered, its hissing quieting. Slowly, the head started to fall; Kassandra scrabbled at its smooth skull, held fast to its longest horn and _thud_ ; Cerastes was dead on the ground and Deimos was helping her down, his eyes wide; going wider when kassandra stumbled.

“Oh gods, Kassandra,” Herodotus breathed, and pulled her in for a hug, squeezing her tight. “You’re alive. You’re… That isn’t your blood, is it? Oh, please tell me it isn’t yours?”

Kassandra breathed out, slow and shaky; smiled at Herodotus, and at Deimos when he hovered too-close at her sword arm. “I’m alright,” She said, “I’m alright.” She grinned, couldn’t help the laugh that bubbled out of her chest, loud and hysterical and gods, _she’d killed it_! All by herself! She hefted open Cerastes’ jaw and peered at its teeth, grinned wider because _yes_ \- she deserved the long, bladed fang glowing gold from its gums. “And look! A nice new sword to replace the one I seem to have lost inside its head!”

“It’s a tooth,” Said Deimos.

Kassandra ripped it out, grabbed the blood-wet root of the fang and tested its weight, hacking it into the dead snake’s head. “And a minotaur horn turned into one of the magic spheres I used to lock Atlantis safely away, your point? Look, it even has a hilt.” She flourished it, and nodded at Herodotus. “See? It’s Isu metal, their power is patterned into it. I’ll take it to a good blacksmith, ask to have a nice handle fitted.”

Herodotus stared at her a moment, shook his head. “What in the world possessed me to make me love you?” He murmured to himself, shook his head again and looked towards the doors. “I think we’d best return to Barnabas, yes? I find it remarkable how some time trapped underground will make him a sight for sore eyes.”

**Notes for the Chapter:**

> [Cerastes](https://en.wikipedia.org/wiki/Cerastes) is in fact a real greek monster. I've butchered it a little, but still.
> 
> And apologies for this last chapter being later than usual, my only excuse is a bout of insomnia making it very difficult to write at the minute because half the time I'm too tired to concentrate and half the time I end up deleting what I've written because I hate it. I'm very sorry about that, but I still have to take my writing a bit slower than I'd like or I'll end up not writing anything.
> 
> That said, not entirely happy with this work so I'll probably come back to this at some point and fix it up a bit. Nothing major, I don't think, but little tweaks here and there.


End file.
